codekata/wind_direction.py at master · julzhk/codekata · GitHub

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"""
implement a function to help an aircraft calculate its heading, given a target and wind direction & speed data
"""

import math
import re


def integerize(func):
    def integerize(*args, **kwargs):
        return int(round(func(*args, **kwargs), 0))

    return integerize


@integerize
def cross_wind(angle, windspeed):
    return math.sin(angle) * windspeed


@integerize
def head_wind(angle, windspeed):
    return math.cos(angle) * windspeed


def angles_to_radians(degrees):
    return float(degrees * math.pi) / 180


def get_runway_heading_in_degrees(runway_code):
    return 10 * int(re.search(r'\d+', runway_code).group())


def wind_info(runway, wind_direction, wind_speed):
    """
    A = Angle of the wind from the direction of travel (radians)
    WS = Wind speed
    CW = sin(A) * WS : Crosswind
    HW = cos(A) * WS : Headwind

    :param runway: (string): "NN[L/C/R]"). NN is the runway's heading in tens of degrees.
                    A suffix of L, C or R may be present and should be ignored.
                    NN is between 01 and 36.
    :param wind_direction:  (int). Direction wind is blowing from in degrees. Between 0 and 359.
    :param wind_speed:  (int). Wind speed in knots
    :return: "(Head|Tail)wind N knots. Crosswind N knots from your (left|right)."
    """
    runway_angle = get_runway_heading_in_degrees(runway_code=runway)
    wind_direction = wind_direction - runway_angle

    headwind = head_wind(angle=angles_to_radians(wind_direction), windspeed=wind_speed)
    crosswind = cross_wind(angle=angles_to_radians(wind_direction), windspeed=wind_speed)
    return "%(head)swind %(headwind)d knots. Crosswind %(crosswind)s knots from your %(side)s." % {
        'head': 'Head' if headwind > 0 else 'Tail',
        'headwind': abs(headwind),
        'crosswind': abs(crosswind),
        'side': 'left' if crosswind < 0 else 'right'
    }


print(cross_wind(1.04719755, 15))
print(head_wind(1.04719755, 15))

test_data = [
    (("18", 170, 15), "Headwind 15 knots. Crosswind 3 knots from your left."),
    (("18", 210, 14), "Headwind 12 knots. Crosswind 7 knots from your right."),
    (("22L", 160, 14), "Headwind 7 knots. Crosswind 12 knots from your left."),
    (("18", 70, 15), "Tailwind 5 knots. Crosswind 14 knots from your left.")
]
for t in test_data:
    print(wind_info(*t[0]))